Yes, projects can be "messy' to grade, which is why schooling still relies so heavily on standardized testing, right and wrong answers, and simple final grades, to make decisions and support organization. The reality is, however, that learning is not so "neat and tidy". Students learn at different paces, and prefer different approaches, as we know. Students also associate differently due to their individual schema of understanding.
Consider this as stated by Travis Dixon on this IB Psychology website:
Schema theory's primary claim is that our mind has mental frameworks that help organize information - these are schemas. These schemas help us to save our cognitive energy when processing the millions of pieces of information, we encounter every day.
Piaget (1977) and Vygotsky (1978) have contributed to this theory over the years. Dixon continues:
A schema is a cluster of knowledge or memory that is stored in the mind. They're also called "cognitive frameworks" as they are a system for categorizing and organizing information and memory.
Also, One way schemas can influence cognition is that they can affect our ability to comprehend new information.
So how, then, is it possible to grade an integrated project fairly and holistically? While it is difficult to capture every schema framework and every preference and thought flow of a student's entire project work, it is important to recognize the process by which the project has been planned, supported and completed. That is, the final grade should not just be decided upon based on the completion of the work, but on how the work was accomplished and the various resources and application time involved.
So, yes, start with the "end in mind" and be clear on the outcomes, then work back and review all of the work completed in order for those outcomes to be met.
Skills Recognition describes holistic assessment as follows:
Holistic assessment (also called 'integrated assessment') focuses on the assessment of whole work activities rather than specific elements.
TIP: Don't undermine the possbile scope of students' work in completing an integrated project.
Coming up, "Is there a Rubric for projects?" Stay tuned...